IRWINDALE (CBSLA.com) — Crews were fighting a compost heap fire in Irwindale, snarling traffic on Arrow Highway near the 605 Freeway late Tuesday evening.

Los Angeles County Fire Department personnel were called to the intersection following a report of a vegetation fire around 8 p.m.

Arrow Highway was closed in both directions between Avenue Barbosa and the 605 Freeway overpass due to emergency equipment in the street. The southbound 605 off-ramp at Arrow was also closed due to heavy smoke.

Motorists were being advised to use alternate routes.

LACoFD estimated the fire could be extinguished by 1 a.m. Wednesday.

No structures were reported threatened.